Adhesive bandages for use by the consumer to treat/dress acute wounds and/or skin irritations are not new. Adhesive bandages 10 as illustrated in FIG. 1, typically include a base layer 20, which is the layer seen by the consumer following application of the bandage to the wound. Such base layer typically has a top surface 21 and bottom surface 22, with the top surface 21 being visible to the consumer upon application to a wound. Such layer is typically formed from a polymeric material, such as a nonwoven sheet or film, or combination thereof. Such nonwoven sheets may for example be produced from meltblown and/or spunbond materials. Such film may be perforated in order to provide for some level of flexibility and breathability. A skin-friendly adhesive 30 is usually placed over the base layer bottom surface 22 to provide a means for attaching the bandage to the consumer. An absorbent pad 40 is traditionally positioned in the center of the base layer, bottom surface, for collecting exudates from a wound. Finally, a non-stick perforated layer 50 is normally positioned over the absorbent pad layer 40, to provide a barrier between the absorbent pad 40 and the wound itself, in order to provide some separation between the collected wound exudates and the wound. A release layer/sheet (not shown) is normally placed over the adhesive and other exposed bottom layers prior to use, as part of the bandage packaging, in order to keep the adhesive from adhering to a substrate for which it is not intended, as well as to protect the bandage from exposure to the environment, until the moment it is to be used. The entire bandage is packaged in a sealed enclosure for further protection. Such bandages are generally passive in nature, in that they serve merely to cover/protect a wound from exposure to the environment during the body's natural healing process.
Typically the absorbent pad in such bandage does not include any medicinal components, although comparatively recently, bandage manufacturers have started including antibiotic agents on bandages to encourage wound healing. For instance, several products are currently being marketed which contain an antiseptic benzalkonium chloride and an antibiotic mixture of polymixin B-sulfate and bacitracin-zinc. Further, patents in this area of technology have described the use of commonly known antiseptics and antibiotics, such as those described in U.S. Pat. Nos. 4,192,299, 4,147,775, 3,419,006, 3,328,259, and 2,510,993. Unfortunately, certain individuals have proven to be allergic to common antibiotics. Therefore, such bandages cannot be freely used by all consumers. Furthermore, there has recently been a push in the medical community to avoid excessive use of antibiotics so as to eliminate the risk that certain bacteria may become resistant to such medications.
There is therefore a need for an adhesive bandage which does not utilize traditional antibiotic treatment, but which does promote wound healing. Furthermore, there is a need for an adhesive bandage which promotes wound healing in multiple ways, but which does not utilize agents which may cause an allergic response in certain individuals. There is also a need for adhesive bandages which promote wound healing through the use of naturally occurring and readily available substances, and that will not add significantly to the price that consumers will pay for such bandages. Still further, there is a need for multifunctional bandages which perform numerous wound healing functions with one wound healing composition.
It has not been new for bandages to accomplish hemostatic functions. For instance, WO99/59647 describes a multilayered haemostatic bandage which comprises preferably a thrombin layer between two fibrinogen layers. The dressing may contain other resorbable materials such as glycolic acid or lactic acid based polymers or copolymers. A hemostatic bandage is also disclosed in WO97/28832. As in the previous reference, such bandage utilizes thrombin, in connection with fibrinogen, adhered to a fibrous matrix. While such bandages absorb fluid, they are directed to a hemostatic function primarily.
U.S. Pat. No. 5,800,372 describes a field dressing for control of exsanguination. Such dressing describes the use of microfibrillar collagen and a superabsorbent polymer in a hemostatic bandage, which both absorbs blood and induces clotting. Again, as in the prior example, such bandage is directed to the primary function of inducing coagulation.
The compound chitosan is a deacetylated product of chitin (C8H13NO5)n, an abundant natural glucosamine polysaccharide found in the ecosystem. In particular, chitin is found in the shells of crustaceans, such as crabs, lobsters and shrimp. The compound is also found in the exoskeletons of marine zooplankton, in the wings of certain insects, such as butterflies and ladybugs, and in the cell wall of yeasts, mushrooms and other fungi.
In addition to being non-toxic, biocompatible and biodegradable, chitosan is also reported in the scientific literature to possess hemostatic, antimicrobial properties and other biomedical attributes. See for instance, Rev Macromol. Chem Phys., C40, 69-83 (2000), Chitin and Chitosan, Editors, G. Skjak-Braek, T. Anthonsen and P. Sanford, Elsevier, (1988); Chitin in Nature and Technology, Editors, R. Muzzarelli, C. Jeuniaux and G. W. Gooday, Plenum Press, (1986).
The biocompatibility of chitosan administered orally and intravenously has been assessed in animals. Its LD50 is over 16 g/Kg in mice, which is higher than for sucrose. LD50 is traditionally defined as the median lethal dose of a substance, which will kill 50% of the animals receiving that dose, with the dose being calculated on amount of material given per gram or kilogram of body weight, or amount per unit of body surface area. See for instance, the 18th Edition of Taber's Cyclopedic Medical Dictionary, p. 1085. The hemostatic properties of Chitosan have also been evaluated in the scientific literature in publications such as Ann. Thor. Surg., 35, 55-60, (1983); J Oral Maxillof Surg, 49, 858-63, (1991).
In recent years, however, attention has been directed in the research community towards biomedical applications of the chitosan compound. In this regard, the use of chitosan in the pharmaceutical and healthcare industry is currently being evaluated. For instance, use of chitosan has been reported in a pharmaceutical product in Pharm Res, 15, 1326-31, (1998). The use of chitosan in the pharmaceutical industry as an excipient has also been explored in Pharm Res, 15, 1326-31, (1998) and Drug Dev. Ind Pharm, 24, 979-93, (1998).
Antimicrobial properties of chitosan have been reported against Gram positive and Gram negative bacteria, including Streptococcus spp., Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Pseudomonas, Escherichia, Proteus, Klebsiella, Serratia, Acinobacter, Enterobacter and Citrobacter spp. See for instance, Muzzarelli et al., in Industrial Polysaccharides: Biomedical and Biotechnological Advances, Eds., V. Crescenzi and S. S. Stivala, Gordon and Breach, pp. 77-88, (1990) and Antimicr. Agents Chemoth., 34, 2019-24, (1990). See also, U.S. Pat. No. 4,659,700, which describes the use of Chitosan in a gel to be applied to wounds.
Chitosan has also been described in the literature to induce repair of tissue containing regularly arranged collagen bundles. See for instance Biomaterials, 9, 247-52, (1988). Additionally, non-woven fabrics made of chitosan fibers have been developed. See for instance, Eur. J. Plastic Surg., 10, 66-76, (1987).
Further, chitin and chitosan derivatives have been studied for their antitumor effects. See for instance, Carbohydr. Res, 151, 403-8, (1986); and Chem. Pharm, 36, 784-90, (1988). Chitosan has additionally been reported as an effective immunomodulator in Vaccine, 4, 151-6, (1986); and K. Nishimura in Chitin Derivatives in Life Sciences, Ed., S. Tokura, Japan Chitin Soc., (1992). Despite all of the research in the chitosan area, there is still a need for a practical application of chitosan that can benefit individuals on a daily basis, such as in the application to acute wounds obtained during a person's daily routine.
While nicotinic acid (niacin), niacinamide (vitamin B3), ascorbic acid and niacinamide ascorbate are known as dietary supplements, for a variety of functions, it is not believed that such uses have been in conjuction with epidermal wound healing functions.